<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<script>
    /*var a = new String('哈哈哈哈');

    var b=5 ;
    console.log(a instanceof String);
    console.log(Boolean(b));*/

    console.log('最大值:'+Number.MAX_VALUE);
    console.log('最小值:'+Number.MIN_VALUE);
    console.log('正无穷:'+Number.POSITIVE_INFINITY);
    console.log('负无穷:'+Number.NEGATIVE_INFINITY);

</script>
<body>

</body>
</html>